Pressure relief valve for a sphygmomanometer

ABSTRACT

A pressure relief valve assembly particularly for use with a sphygmomanometer having a housing, an internal axial bore for passing pressurized air through the housing, a transverse bore intersecting the axial bore and communicating with the exterior of the housing, a flexible, resilient member mounted within the axial bore and sealing off the intersecting end of the transverse bore, and actuating means extending through the transverse bore for depressing the resilient member away from sealing relationship with the transverse bore to permit selective relief of the pressurized air.

United States Patent 1191 Stewart 1 Dec. 18, 1973 PRESSURE RELIEF VALVEFOR A SPHYGMOMANOMETER [75] Inventor: James M. Stewart, West Palm Beach,Fla.

[73} Assignee: Stewart Research, lnc., West Palm Beach, Fla.

[22] Filed: Sept. 7, 1971 21 App]. No.: 178,212

521 US. Cl 128/2.0S G, 251/259, 251/145 51 Int. Cl A6lb 5/02 [58] Fieldof Search 251/145, 259; 128/205 0 [56] References Cited UNlTED STATESPATENTS 3,504,663 4/1970 Edwards l28/2.05 G 3,620,250 11/1971 Wieck251/145 X 2,955,6l6 10/1960 Jarret et al 251/259 Primary Examiner-SamuelScott Assistant E.\'an1incrlra S. Lazarus Attorney-Marcus B. Finnegan etal.

[5 7] ABSTRACT A pressure reliefvalve assembly particularly for use witha sphygmomanometer having a housing, an internal axial bore for passingpressurized air through the housing, a transverse bore intersecting theaxial bore and communicating with the exterior of the housing, aflexible, resilient member mounted within the axial bore and sealing offthe intersecting end of the trans verse bore, and actuating meansextending through the transverse bore for depressing the resilientmember away from sealing relationship with the transverse bore to permitselective relief of the pressurized air.

9 Claims, 5 Drawing Figures PRESSURE RELIEF VALVE FOR A SPHYGMOMANOMETERThis invention relates to a pressure relief valve and more particularly,to a new and improved pressure relief valve assembly for asphygmomanometer that permits the operator to accurately andconveniently control the rate of relief of pressurized air. v

In the measuring of blood pressure with a sphygmomanometer, a mainartery is compressed by an inflatable cuff wrapped around an arm or aleg until the flow of blood therethrough is completely stoppedindicating that the cuff has been inflated to a pressure above that ofthe bloods pressure. The air is then released slowly while the physicianlistens for changing sound of the pulse. First evidence of passage ofblood through the artery is detected, and then the air is furtherreleased slowly until the character of the sound again changes,indicating that blood is flowing normally through the artery.Observation of a pressure gauge by the physician at these two pointsgives the necessary systolic and diastolic pressures. During use of theinstrument, it is important that the physician be able to release airfrom the cuff very slowly, especially when making the systolic anddiastolic observations, and also that he be able to rapidly release airfrom the cuff after these values have been observed.

Accordingly, it is a primary object of the present invention to providea new and improved pressure relief valve, particularly for use with asphygmomanometer, whereby pressurized air or other gas in the system maybe conveniently and accurately released at a controllable slowrate or ata rapid rate as desired by the operator.

It is a further object of this invention to provide a new and improvedpressure relief valve for a sphygmomanometer that is simplified inconstruction and reliable and efficient in use and that permits theoperator to more accurately and conveniently control the rate of reliefof the pressurized air than has been provided heretofore in prior artsystems.

Additional objects and advantages of this invention will be set forth inpart in the description which follows and in part will be obvious fromthe description or may be learned by practice of the invention, theobjects and advantages being realized and attained by means of theinstrumentalities, devices, and combinations particularly pointed out inthe appended claims.

To achieve the foregoing objects and in accordance with its purpose, thepressure relief valve assembly of this invention, as embodied andbroadly described, comprises a valve housing having an internal axialbore and an inlet end and an outlet end communicating with the bore, atransverse bore intersecting the axial bore and communicating with theexterior of the housing, a flexible resilient member mounted within theaxial bore and sealing off the intersecting end of the transverse bore,and actuating means extending through the transverse bore for depressingthe resilient member away from sealing relationship with the transversebore and thereby permitting selective relief of the pressurized Theaccompanying drawings which are incorporated and constitute a part ofthis specification illustrate an embodiment of the invention andtogether with the description serve to explain the principles of theinvention.

Of the drawings:

FIG. 1 is a perspective view ofa sphygmomanometer embodying the pressurerelief valve of the present invention and utilizing a dial pressuregauge;

FIG. 2 is a side sectional view of a valve assembly of the presentinvention in a closed position;

FIG. 3 is a side sectional view of the valve similar to FIG. 2 but withthe valve in a full open position;

FIG. 4 is a sectional view taken along the lines 4-4 of FIG. 2; and

FIG. 5 is a sectional view taken along the lines 55 of FIG. 3.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory but arenot restrictive of the invention.

Reference will now be made in detail to a preferred embodiment of theinvention, an example of which is illustrated in the accompanyingdrawings.

For convenience, the invention will be described as it relates for usewith a sphygmomanometer. It will be appreciated by those skilled in theart,'however, that the valve is equally useful in other applicationswhere it is necessary to control the rate of relief of a gas or otherfluid in a pressurized system.

A typical sphygmomanometer is illustrated in FIG. I and consistsbasically of an inflatable cuff and a dial pressure gauge 12 connectedto the cuff through a tube 14 for measuring air pressure in the inflatedcuff. A bulb 16 for inflating the cuff is provided and a tube 18connects to the cuff and a coupling 20 for passing air from the bulb tocuff 10.

The new and improved pressure relief valve assembly of the presentinvention is generally indicated as 22 and is connected between coupling20 and a suitable coupling 24 on the end of inflating bulb 16, thuslocating the valve for convenient manipulation by the thumb of theoperator.

With reference to more detailed views of the valve, as shown in FIGS. 2and 3, the pressure relief valve assembly of this invention includes avalve housing having a gas inlet end 32 for connection to coupling 24 onbulb l6 and a gas outlet end 34 for connection to coupling 20. As shownin FIGS. 2 and 3, inlet and outlet ends 32 and 34 are provided, forexample, with a threaded internal bore that screws onto a similarthreaded shank (not shown) on the ends of couplings 24 and 20,respectively. It will be appreciated, of course, that any other suitableconnecting means, such as a bayonet or friction-type fit, may be usedfor con necting the valve in the system or that the valve and couplingsmay be made of one piece without departing from the scope of the presentinvention.

As best shown in FIGS. 2 and 3, valve housing 30 has an internal axialbore 36 communicating with inlet end 32 and outlet end 34 and atransverse bore 38 intersecting axial bore 36 at 40 and communicatingwith the exterior of housing 30. Preferably, housing 30 is constructedof plastic or any other suitable material.

In accordance with the invention, a flexible, resilient member ismounted within axial bore 36 and adjacent transverse bore 38 to seal offthe intersecting end 40 of the, transverse bore.

As embodied and as shown in FIGS. 2 and 3, this member comprises adeformable and resilient sleeve 42, preferably of a rubbery materialsuch as silicon rubher, having an internal passageway 44 and mounted intight-fitting relationship with the internal surfaces of axial bore 36.Thus, when sleeve 42 is in its at-rest or normal position, as shown inFIG. 2, it effectively seals off the intersecting end 40 of transversebore 38 and prevents the escape of pressurized air from the valve.

As more fully described below and as best shown in FIGS. 4 and 5, sleeve42 has a thickened wall portion 46 located adjacent transverse bore 38to provide more rigidity and greater resistance to wear to the sleeve.Means are further provided for orienting and retaining sleeve 42 inposition in axial bore 36, which means comprises a shoulder 48 in bore36 facing the inlet end 32 of the valve and a corresponding lip 50 onthe inlet end of sleeve 42 that rests against shoulder 48 and keeps thesleeve in position.

In accordance with the invention, actuating means are provided thatextend through transverse bore 38 to depress tubular sleeve 42 away fromsealing engagement with transverse bore 38 and thereby permit selec tiverelief of pressurized air from the valve.

As embodied, and as best shown in FIGS. 2 and 3, this means comprises avalve plunger, generally 52, axially movable with respect to transversebore 38. Plunger 52 consists of a stem portion 54 located within bore 38and integral head portion 56 outside of and of greater diameter thanbore 38. Further, the tip of plunger head 56 is generally conicallyshaped to provide a cam surface 58 for actuation by a control member,generally 60, pivotally mounted at 62 to valve housing 30.

As best shown in FIGS. 2 and 3, control member 60 consists of a leverarm 64, having an upper thumbengaging surface, movable between avalve-closed position, as shown in FIG. 2, and a valve full-openposition, as shown in FIG. 3. Lever arm 64 also has a lower cam surface66 cooperating with cam surface 58 on plunger head 56 to effectdepression of plunger 52 and sleeve 42 as the arm moves between closedand opened positions. As best shown in FIGS. 2 and 3 and as more fullydescribed below in connection with the operation of the device, as lever64 moves from closed towards open position, cam 66 gradually depressesplunger 52 and sleeve 42 to permit slow release of the pressurized air.After the center part 67 of cam 66 passes over the top center of camsurface 58, plunger 52 and sleeve 42 are locked in full-open position topermit rapid release of air from the valve.

In accordance with the invention, spring means are further provided forbiasing valve plunger 52 away from sleeve 42 and toward the valve-closedposition shown in FIG. 2. As embodied and as shown in FIGS. 2 and 3, thespring means comprises a leaf spring 68 mounted at 70 to housing 30 andacting against the underside 72 of plunger head 56 to keep the plungerup and towards the valve-closed position. Preferably, and as best shownin FIGS. 4 and 5, spring 68 extends along both sides of plunger head 56and has an aperture 74 for valve stem 54.

In operation of a sphygmomanometer with the valve assembly of thisinvention and with the valve in closed position, as shown in FIG. 2, thephysician squeezes bulb l6, feeding pressurized air through coupling 24,valve inlet 32, passageway 44 of sleeve 42, valve outlet 34, coupling20, and tube 18 into inflatable cuff 10. With the valve in closedposition, sleeve 42 seals off transverse bore 38 preventing the escapeof air from the valve but does not interfere with the passage of air tothe cufi'. While the resilience of the sleeve provides a significantdegree of sealing capability it will be appreciated that additionalsealing is also provided by the increased internal air pressure passingthrough the in terior of the sleeve.

A one-way valve (not shown) is generally provided in coupling 24 toprevent the air from returning to bulb 16 after pressure is released onthe bulb and pumped again by the physician.

After the cuff has been inflated to the desired degree as discussedabove, the physician gently depresses the rearward or right-hand end 74(see FIG. 2) of lever 64 causing cam surface 66 to ride up on camsurface 58 and slowly depress plunger 52 and deform sleeve 42 to permitslow relief of air from the system. With reference to FIGS. 2 and 3, itcan be seen that as the lever moves from the point shown in FIG. 2 tothe position shown in FIG. 3, the degree of camming and hence the rateof release of the air can be accurately controlled by the thumb of thephysician. Thus, during this variable phase of operation between thepositions shown in FIGS. 2 and 3, the air may be permitted to escape invarying degrees merely by altering the relative position of the camlever through finger pressure. This permits the physician tocontrollably release the air very slowly at first so that both thesystolic and diastolic pressures can be observed. Once these readingsare observed, the physician pushes all the way down to the right-handend of lever 64 clicking the center point 67 of cam 66 over the top ofcam surface 58 and locking the valve in full-open position to permitrapid release of air and quick removal of the cuff.

Before the next cycle of function is desired, the forward or left-handportion 76 (see FIG. 2) of lever 64 is depressed causing arm 66 torelease valve plunger 52 and close the valve.

Thus, it will be apparent that the foregoing invention provides a uniqueand convenient valve assembly for a sphygmomanometer that permitsrelease of the pressurized air at both a controllable slow rate and at arapid rate as desired by the operator.

The invention in its broader aspects is not limited t the specificdetails shown and described and departures may be made from such detailswithout departing from the principles of the invention and withoutsacrificing its chief advantages.

What is claimed is:

l. A sphygmomanometer comprising an inflatable cuff, a bulb providingair pressure, an indicating gauge connected to the cuff for measuringair pressure in the cuff, a tube communicating with the cuff, and apressure-relief valve assembly connecting the bulb to the tube forpermitting selective relief of the pressurized air from the cuff, saidvalve assembly comprising a valve housing having an inlet end connectedto the bulb and an outlet end connected to the tube and an internal,axial bore communicating with the inlet and outlet ends, a transversebore substantially perpendicular to and intersecting the axial bore andcommunicating with the exterior of the housing, a resilient annularsleeve mounted tightly within the axial bore and sealing off theintersecting end of the transverse bore in normal position whileproviding communication between the inlet and outlet ends of thehousing, and actuating means including a valve plunger axially movablewithin the transverse bore for acting against said sleeve, said plungerbeing spring biased in a direction away from the resilient sleeve, and acontrol lever limiting outward movement of the plunger and forselectively depressing the plunger inwardly against the sleeve to movethe sleeve away from sealing relationship with the transverse bore andthereby permit varied relief of the pressurized air from the inflatablecuff.

2. The assembly of claim 1, wherein the sleeve has a thickened wallportion adjacent the transverse bore.

3. The assembly of claim 1, including means for retaining the sleeve inthe axial bore against the force of pressurized air passing through thevalve assembly.

4. The assembly of claim 3, wherein said retaining means comprises ashoulder in the bore facing the inlet end of the valve and acorresponding lip around one end of the sleeve cooperating with theshoulder to keep the sleeve in position.

5. The assembly of claim 1, wherein the control lever comprises a leverarm pivotally mounted on the housing said lever arm having a cam surfacecooperating with a cam surface on the valve plunger and operable betweena valve-closed position when the resilient sleeve is sealed against thetransverse bore and a valve full-open position when the resilient sleeveis depressed its maximum distance away from the transverse bore topermit rapid relief of pressurized air.

6. The assembly of claim 5, including means for locking the lever infull-open position.

7. The assembly of claim 6, in which the cooperating cam surfaces lockthe lever in full-open position.

8. The assembly of claim 1, including spring means biasing the valveplunger away from the resilient sleeve.

9. The assembly of claim 8, wherein the valve plunger includes a stemportion located in the transverse bore and an upper head portion ofgreater diameter than the stem an wherein said spring means acts againstthe underside of the valve plunger head to bias the plunger away fromthe resilient sleeve.

1. A sphygmomanometer comprising an inflatable cuff, a bulb providingair pressure, an indicating gauge connected to the cuff for measuringair pressure in the cuff, a tube communicating with the cuff, and apressure-relief valve assembly connecting the bulb to the tube forpermitting selective relief of the pressurized air from the cuff, saidvalve assembly comprising a valve housing having an inlet end connectedto the bulb and an outlet end connected to the tube and an internal,axial bore communicating with the inlet and outlet ends, a transversebore substantially perpendicular to and intersecting the axial bore andcommunicating with the exterior of the housing, a resilient annularsleeve mounted tightly within the axial bore and sealing off theintersecting end of the transverse bore in normal position whileproviding communication between the inlet and outlet ends of thehousing, and actuating means including a valve plunger axially movablewithin the transverse bore for acting against said sleeve, said plungerbeing spring biased in a direction away from the resilient sleeve, and acontrol lever limiting outward movement of the plunger and forselectively depressing the plunger inwardly against the sleeve to movethe sleeve away from sealing relationship with the transverse bore andthereby permit varied relief of the pressurized air from the inflatablecuff.
 2. The assembly of claim 1, wherein the sleeve has a thickenedwall portion adjacent the transverse bore.
 3. The assembly of claim 1,including means for retaining the sleeve in the axial bore against theforce of pressurized air passing through the valve assembly.
 4. Theassembly of claim 3, wherein said retaining means comprises a shoulderin the bore facing the inlet end of the valve and a corresponding liparound one end of the sleeve cooperating with the shoulder to keep thesleeve in position.
 5. The assembly of claim 1, wherein the controllever comprises a lever arm pivotally mounted on the housing said leverarm having a cam surface cooperating with a cam surface on the valveplunger and operable between a valve-closed position when the resilientsleeve is sealed against the transverse bore and a valve full-openposition when the resilient sleeve is depressed its maximum distanceaway from the transverse bore to permit rapid relief of pressurized air.6. The assembly of claiM 5, including means for locking the lever infull-open position.
 7. The assembly of claim 6, in which the cooperatingcam surfaces lock the lever in full-open position.
 8. The assembly ofclaim 1, including spring means biasing the valve plunger away from theresilient sleeve.
 9. The assembly of claim 8, wherein the valve plungerincludes a stem portion located in the transverse bore and an upper headportion of greater diameter than the stem an wherein said spring meansacts against the underside of the valve plunger head to bias the plungeraway from the resilient sleeve.